Ugly Betty


“Ugly Betty”

That’s what I have named my amp project. she’s a 1937 Bogen  PA amplifier. At a spry 71 years,  she is past her prime to say the least but I think with some TLC she might have a second chance at life as a Guitar amp.

The purpose of this page is to act as a journal to document my virgin attempt at vintage iron restoration. Hope I don’t get electrocuted


bogenschematicGot my vintage Bogen amp project from Ebay yesterday and last night when Tim came over we plugged it in for the first time. All the tubes except for 1 showed signs of firing up. The 70 year old amp was ALIVE! BWAHAHAH. then just as suddenly the rectifyer tube started to spark. It was a tense 8 or 10 seconds but had to shutdown in a hurry . This morning I hit Ebay for a replacement for the rectifyer I have a feeling this project is going to nickle and dime me to death.and I have only started 😛


While her new tube is on order, I have replaced the screw on microphone type connectors with shiney new 1/4″ phono jacks to accommodate guitar inputs.

There is something magical about vintage electronics. The smell of old solder, comming off a hot iron, as if the smoke had been trapped there in the led connections for over half a century, Old cloth insulated wire, brittle from the years.  Once bent into place by skilled hands belonging to somebody’s great grandmother, hands surly now gnarled by arthritis or more likely at this age, hands belonging to a corpse in a grave.

Magical glass tubes glowing warm to the touch. Inside, literally boiling electrons free from their tungsten confines reaching lethal voltages a thousand times that of the input signal.

Poetry in electrical engineering


modified_bogen_e14_shematic_inverseBeen thinking of how to re use the phono channel as a gain stage for tube distortion. So I have removed the phono circuitry and repurposed the second half of 7F7 a a gain stage. Hope fully this will not cause her to explode into flames. when current is applied. BUAHAHAHA!

I think I might have melted one of Tim’s rectifyer tubes last night. The 110 AC power comes in and is put through an rectifyer tube to turn it into pulsating DC.  I didn’t have the 5Y4g rectifier tube I ordered yet but I had a 5y3. After a little research on the internets I found that supposedly the 2 tubes are the same , sans pinout. so I took  an iron to Betty and re-wired her socket.  but alass…. no joy

5y4New Rectifier is here WHOO HOO!. Should U just plug it in? or should I measure all the 70 year old capacitors first?

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